Gaseous electric discharge lamp device



May 26, 1936 c. BOL ET AL 2,042,139

GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Filed Sept. 18, 1934 629, 1 2 15 9/ fil m INVENTORS la /z s 62 JQKJZZha/mw 5 g 2/ 2 w BY 74%, 140W.

ATTORN EY Patented May 26, 1936 UNITED STATES PATENT. oFF c GASEOUS ELECTRIC DISCHARGE LAW DEVICE Cornelis B01 and Hendrik A. W. Klinkhamer, 7 Eindhoven, Netherlands, assignors to General Electric Company, a corporation of New York Application September 18, 1934, Serial No. 744,488

3 Claims.

The present invention relates generally to gaseous electric discharge lamp devices and more particularly the invention relates to starting and operating circuits for a plurality of such devices 5 similar to that described in co-pending application, Serial Number 645,283, filed December 1, 1932, the inventor being Hendrik A. W. Klinkhamer.

' In the co-pending application an illuminating system is disclosed which comprises a plurality of gas filled electric discharge devices, each having a thermionic electrode, and a pluralityof transformers, one for each of said devices, having the primaries thereof connected in series to the terminals of a current source. The operating voltage of such devices is appreciably lower than the starting potential thereof. The vo1tage of the current source in such a system must be greater than the sum of the operating voltages of the various devices but need not equal the sum of the starting potentials of the devices. It is understood, of course, that the starting and operating, voltages of each lamp device is measured between the terminals of the transformer across which the lamp device is connected rather than between the electrodes of the lamp device.- As a result of the cooperative action of the thermionic electrodes and of the series-wired transformers, the potential necessary to start the lamp devices in the system is smaller than the sum of the starting potentials of the devices. When external impedance consistingof ohmic resistances are used, this has the advantage that these resistances can be. made smaller so that the energy which is lost therein is reduced. If, as is customary, the external impedance consists of an auto-inductance then this also can be made smaller which results in a better performance factor. The number of lamp devices which can be started on a certain 4 voltage in a circuit of this type is greater than in prior circuits. I

The object of the present invention is to improve illuminating systems' ofthe above type so that the number of lamp devices in the system 4 which can be started on a certain voltage can be increased. Another object of the invention is to increase the efiiciency of illuminating systems of this type. Still further objects and advantages attaching to the device and to its use and opera- 50 tion will be apparent to those skilled in the art from the following particular description.

The invention attains its objects by connecting a condenser across the conductors connecting the transformers in series and in series with a choke 55 coil. Starting of the dischargelamps is facili- Germany September 30, 1933 tated by the arrangement. The condenser, is cut out of circuit after starting of the discharge lamps. The invention is particularly valuable when the thermionic electrodes of the discharge lamps are heated by the discharge rather than by a special heater current. In this case the con-' denser is connected into the circuit until the electrodes have reached the temperature necessary for ordinary operation that is, a temperature at which the electrodes emit a heavy stream of electrons.

Preferably, the condenser and the choke coil are constructed in such manner that they are in resonance or almost in resonance for the third harmonic of the current supply source. For a 15 given size of the self inductance the size of the capacity at which the best effect is produced is easily determined by means well known in the art.

Preferably, the transformers are so constructed that they are strongly saturated when idle that 20,

is, before the discharge has started in the lamps and after current is applied to the circuit. The choke coil is preferably constructed so that it is undersaturated during this period. Thisalso exercises a favorable influence on the starting of 25 the discharge lamps.

The invention will be readily understood from an inspection of the accompanying drawing and a perusal of the following detailed description.

In the drawing 3 Fig. 1 is a schematic representation of a vcircuit embodying the invention, i

Fig. 2 illustrates a choke-coil useful in the circuit shown in Fig. 1, and l Fig. 3 illustrates an electro-magnetic switch 5 useful in the circuit of Fig. 1. I The new and novel illuminating system is connected across the terminals I of an alternating current source and comprises a plurality of transformers 2 the primary coils 3 of which are con- 40 nected in series with each other and to the terminals I through the choke coil 4. The ends of the secondary transformer coils 5 are connected with the thermionic electrodes 1 of the U shaped discharge lamps 6, which are filled with a starting, rare gas, such as neon, at a pressure of 1 to 10 mm., and also contain an amount of vaporizable material, such as sodium, the vapor of which participates intensively in the light emission of the discharge lamp. The gaseous atmosphere in the lamps'6 comprises a fixed gas, a mixture of fixed gases, a metal vapor, or a mixture of metal vapors, when desired. The vapor of such metals as rhubidium, caesium, cadmium, magnesium, and mercury are useful as light emitting elements in such discharge lamps. The electrodes I are brought to a temperature required for electron emission by means of the discharge, although it is also possible, to conduct a. special heater current through these electrodes for this purpose, when desired.

Between the leads 8 and 9 acondenser I0 is connected in series with a switch II. In the closed position of the switch II the condenser is connected in series wtih the choke coil 4 and in parallel with the transformer coils 3. It is recommended to so build the switch II that, in closing, the condenser I I] is switched in over a resistance II, which is switched out again when the switch closes completely as shown in Fig. 3.

When the illuminating system is started into operation the switch II is closed and the supply voltage is conducted to the lamps 6. It is obvious that the condenser I0 facilitates the starting of the various discharge lamps. The condenser I0 is preferably connected into the circuit until the electrodes I have reached their operating temperature. When said electrodes I have attained this temperature the switch II preferably is opened to out out of circuit said condenser I0 during the operation of the lamp device, because, letting the condenser switched in longer can unfavorably influence the life of the discharge lamps.

Preferably, the condenser I I! is of such structure a that it is in resonance or almost in resonance with the choke coil 4 for the third harmonic of the alternating current source I. The most favorable value for the condenser can be determined in a simple manner by experiments.

Preferably the transformers 2, which can also be auto-transformers, are so constructed that they are strongly saturated when idle, whereas the choke-coil 4 is so built that 'it is undersaturated during this period.

The choke-coil 4 is constructed in the manner shown in Fig. 2, when desired. On the core I2 two coil parts I3 and I4 are arranged of which the part I3 has a fixed position while the part It is movable in a vertical direction and is hun upon the balance I5 to which the counterweight I6 is fastened. The coil'parts I3 and I4 are so wound that they attract each other. This attractive power and the inherent weight of the coil part I4 equalize the counterweight I6. With an increasing current strength the gap between the coil parts I3 and I 4 becomes smaller so that the leakage field becomes weaker and the self induction becomes greater. The greater attractive power between the coil partsis here equalized by the greater lever arm of the counterweight IS.

The switching out of circuit of the condenser I0 after starting of 'the discharge lamps is done by automatic means, when desired. For this purpose, the greater intensity of the current which fiows through the series circuit after starting of the lamps 6 is utilized, when desired. This current, for instance, can fiow through the winding of an-electro-magnetic relay which operates the switch II. For the purpose of energizing the relay the leakage field of the choke coil 4 is used,

when desired. Because of the increase ofthe current after starting of the discharge lamps this leakage field becomes stronger and is utilized'to energize a magnetic relay, when desired.

When desired, the switching mechanism has the structure shown in Fig. 3 of the drawing.

The switch shown in Fig. 3 comprises a pivoted arm II electrically connected to the line 8, having an armature I9 of the electro-magnetic relay I8,

thereof.

I9 mounted along the length thereof and having a bridging contact 25 mounted on the free end Said contact 25 slides across, makes contact with and bridges the gap between any two successive contactsZII, 2|, 22, or 23. Said contacts 20 and 23 are neutral and said contacts 2| and 22 are connected to the resistance I I. Said condenser I0 is connected to said contact 22. The coil I8 is connected into the line 9.

Before current is applied to the system the contact 25 is in contact with the contact v2t. After current is applied to the system and before the electrodes, have reached their operating temperature the contact 25 is moved by coil I8 attracting armature I9 to the position shown in the drawing, that is, in contact with-the contact 22 which connects the condenser II] in parallel with the transformers 3 and in series with the inductance 4. In assuming this position the contact 25 first comes into contact with contact 2!, which connects the resistance I1 and the condenser Ill into the circuit, then bridges the contacts 2i and 22, which cuts the resistance I! out of circuit. When the electrodes have reached their operating temperature current flow through coil I8 increases and the switch I I is m0 ed into contact with contact 23 and out of conta t with contact 22 to cut condenser II] out of circuit. When the system is turned ofi arm II is drawn back to its original position by spring 23.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and.scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is: I

1. An illuminating system comprising in combination a plurality of transformers connected in series across the terminals of a current source, a. plurality of gaseous electric discharge lamp devices, each of said lamp devices having a thermionic electrode and being connected across the terminals of one of said transformers, an inductance connected in series with said transformers,

a condenser connected in parallel with said transterminals of one of said transformers, an inductance connected in series with said transformers, a condenser connected in parallel with said transformers and in series with said inductance, said condenser and said inductance being in resonance for the third harmonic of said current source, and

means to cut said condenser out of circuit when the thermionic electrodes have attained their operating temperature.

3. An illuminating system comprising in combination a plurality of transformers connected in series across the terminals of a current source, a plurality of gaseous electric discharge lamp devices, each of said lamp devices having a. thermionic electrode and being connected across the terminals of one of said transformers, an inductance connected inseries with said transformers, said transformers being saturated and said inductance being unsaturated after current is applied to said system and before the discharge in said lamps has started, a condenser connected inparallel with said'transfonners and in series with said inductance, and means to cut said condenser out of circuit when the thermionic electrodes have attained their operating temperature.

. CORNEHS BOL. 

